Dive, Luxury, and Premier Balls are some of my all time favorites, all of which came about in RSE. <3 I hate that you only get one Luxury Ball in RSE though (I'm sure there is another way, but being able to buy them would have been much more convenient!). I just love the designs, even though they're not particularly the most useful. Not many times you would need the Dive Ball (Relicanth tho??), not many friendship evolutions in RSE either, and Premier Ball is just a prettier Pokeball, and that obviously gets outclasses quickly. But oh well, I'm an aesthetic person so I'd pick these over Ultra Ball. :)

20,000 posts DEAR GOD what is my life

You can get more Luxury balls by beating a Master Rank contest with a Pokémon that already has got the ribbon.

I like all the same ones as Syd. I found the Repeat Ball pretty useful as well, especially after I finished the PokéDex.